Soils and Vegetation

Brazil's tropical soils produce 70 million tons of grain crops per
year, but this output is attributed more to their extension than their
fertility. Despite the earliest Portuguese explorers' reports that the
land was exceptionally fertile and that anything planted grew well, the
record in terms of sustained agricultural productivity has been
generally disappointing. High initial fertility after clearing and
burning usually is depleted rapidly, and acidity and aluminum content
are often high. Together with the rapid growth of weeds and pests in
cultivated areas, as a result of high temperatures and humidity, this
loss of fertility explains the westward movement of the agricultural
frontier and slash-and-burn agriculture (see Glossary); it takes less
investment in work or money to clear new land than to continue
cultivating the same land. Burning also is used traditionally to remove
tall, dry, and nutrient-poor grass from pasture at the end of the dry
season. Until mechanization and the use of chemical and genetic inputs
increased during the agricultural intensification period of the 1970s
and 1980s, coffee planting and farming in general moved constantly
onward to new lands in the west and north. This pattern of horizontal or
extensive expansion maintained low levels of technology and productivity
and placed emphasis on quantity rather than quality of agricultural
production.

The largest areas of fertile soils, called terra roxa (red
earth), are found in the states of Paraná and São Paulo. The least
fertile areas are in the Amazon, where the dense rain forest is. Soils
in the Northeast are often fertile, but they lack water, unless they are
irrigated artificially.

In the 1980s, investments made possible the use of irrigation,
especially in the Northeast Region and in Rio Grande do Sul State, which
had shifted from grazing to soy and rice production in the 1970s.
Savanna soils also were made usable for soybean farming through acidity
correction, fertilization, plant breeding, and in some cases spray
irrigation. As agriculture underwent modernization in the 1970s and
1980s, soil fertility became less important for agricultural production
than factors related to capital investment, such as infrastructure,
mechanization, use of chemical inputs, breeding, and proximity to
markets. Consequently, the vigor of frontier expansion weakened.

The variety of climates, soils, and drainage conditions in Brazil is
reflected in the range of its vegetation types. The Amazon Basin and the
areas of heavy rainfall along the Atlantic coast have tropical rain
forest composed of broadleaf evergreen trees. The rain forest may
contain as many as 3,000 species of flora and fauna within a
2.6-square-kilometer area. The Atlantic Forest is reputed to have even
greater biological diversity than the Amazon rain forest, which, despite
apparent homogeneity, contains many types of vegetation, from high
canopy forest to bamboo groves.

In the semiarid Northeast, caatinga , a dry, thick, thorny
vegetation, predominates. Most of central Brazil is covered with a
woodland savanna, known as the cerrado (sparse scrub trees and
drought-resistant grasses), which became an area of agricultural
development after the mid-1970s. In the South (Sul), needle-leaved
pinewoods (Paraná pine or araucaria) cover the highlands; grassland
similar to the Argentine pampa covers the sea-level plains. The Mato
Grosso swamplands (Pantanal Mato-grossense) is a Florida-sized plain in
the western portion of the Center-West (Centro-Oeste). It is covered
with tall grasses, bushes, and widely dispersed trees similar to those
of the cerrado and is partly submerged during the rainy season.

Brazil, which is named after reddish dyewood (pau brasil ),
has long been famous for the wealth of its tropical forests. These are
not, however, as important to world markets as those of Asia and Africa,
which started to reach depletion only in the 1980s. By 1996 more than 90
percent of the original Atlantic forest had been cleared, primarily for
agriculture, with little use made of the wood, except for araucaria pine
in Paraná.

The inverse situation existed with regard to clearing for wood in the
Amazon rain forest, of which about 15 percent had been cleared by 1994,
and part of the remainder had been disturbed by selective logging.
Because the Amazon forest is highly heterogeneous, with hundreds of
woody species per hectare, there is considerable distance between
individual trees of economic value, such as mahogany and cerejeira
. Therefore, this type of forest is not normally cleared for timber
extraction but logged through high-grading, or selection of the most
valuable trees. Because of vines, felling, and transportation, their
removal causes destruction of many other trees, and the litter and new
growth create a risk of forest fires, which are otherwise rare in rain
forests. In favorable locations, such as Paragominas, in the
northeastern part of Pará State, a new pattern of timber extraction has
emerged: diversification and the production of plywood have led to the
economic use of more than 100 tree species.

Starting in the late 1980s, rapid deforestation and extensive burning
in Brazil received considerable international and national attention.
Satellite images have helped document and quantify deforestation as well
as fires, but their use also has generated considerable controversy
because of problems of defining original vegetation, cloud cover, and
dealing with secondary growth and because fires, as mentioned above, may
occur in old pasture rather than signifying new clearing. Public
policies intended to promote sustainable management of timber
extraction, as well as sustainable use of nontimber forest products
(such as rubber, Brazil nuts, fruits, seeds, oils, and vines), were
being discussed intensely in the mid-1990s. However, implementing the
principles of sustainable development (see Glossary), without
irreversible damage to the environment, proved to be more challenging
than establishing international agreements about them.